Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D9/00—Chemical paint or ink removers
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/22—Organic compounds
  • C11D7/26—Organic compounds containing oxygen
  • C11D7/261—Alcohols; Phenols
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D9/00—Chemical paint or ink removers
  • C09D9/005—Chemical paint or ink removers containing organic solvents
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/50—Solvents
  • C11D7/5004—Organic solvents
  • C11D7/5022—Organic solvents containing oxygen
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/22—Organic compounds
  • C11D7/24—Hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/22—Organic compounds
  • C11D7/26—Organic compounds containing oxygen
  • C11D7/267—Heterocyclic compounds

Definitions

• This invention relates to compositions for removing or stripping paint, varnish, and like coatings from wood and metal surfaces.
• compositions for removing protective coatings have generally utilized methylene chloride and other halogenated aliphatic hydrocarbons.
• Paint and varnish removers are of two main types according to method of use: application removers and immersion removers.
• Application removers are usually applied by brushing or spraying and are used for small jobs or for items that cannot be immersed.
• Immersion removers are used as either cold or hot baths where it is practical and cost efficient to install equipment that can strip numerous items.
• Cold baths contain solvents such as methylene chloride, and hot paths often contain caustic soda.
• aliphatic alcohols or cyclic aliphatic oxides such as tetramethylene oxide
• an aliphatic acid ester such as ethyl acetate in acetone
• a surface active agent such as a long chain alkylbenzene sulfonate
• a film-forming base material such as wax, cellulose nitrate, and cellulose acetate
• the composition includes methylene chloride as the preferred sole active organic solvent plus a second component such as benzene, methanol, and acetone to form preferred binary mixtures.
• compositions useful for removing coatings and finishes such as paints, varnishes, lacquers, shellac, gums, and natural and synthetic resins.
• U.S. Pat. No. 3,538,007 discloses a paint stripper comprising 54-77 parts of chlorinated liquid hydrocarbon solvent, 1-4 parts of carboxylic acid having 1-4 carbons, 1-6 parts of propargyl alcohol, 0-2 parts of non-ionic wetting agent, 0-15 parts of liquid aromatic hydrocarbon solvents, 0-6 parts of a coupling agent, 0-30 parts of phenol or alkyl substituted phenol, 0-2 parts of a thickener, and 0-2 parts of an evaporation retarder.
• the aromatic liquid hydrocarbon can be benzene, toluene, or xylene.
• U.S. Pat. No. 3,574,123 describes a paint stripper comprising 50-90 parts of a chlorinated liquid hydrocarbon solvent, 2-15 parts of a lower aliphatic alcohol or glycol ethers, 0.1-15 parts of a lower carboxylic acid, 2-30 parts of hydroxybenzenes, 2-10 parts of a fatty acids sulfonate or a salt of a fatty amine carboxylic acid, and 0.1-10 parts of aqueous ammonium bifluoride.
• This composition can also contain inert organic aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, otho-ethyltoluene, di-ethylbenzene, and isopropyl benzene, the lower alkyl substituted benzenes boiling at 170° F. and higher being preferred.
• inert organic aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, otho-ethyltoluene, di-ethylbenzene, and isopropyl benzene, the lower alkyl substituted benzenes boiling at 170° F. and higher being preferred.
• U.S. Pat. No. 3,592,691 describes the removal of photo resist mask residuals from a semiconductor substrate by immersing the substrate in a photoresist solvent and heating the solvent at 150°-250° C. and at a pressure of about 300 psig for a time period of 1/4-3 hours.
• the solvent composition comprises trichloroethylene, isopropanol, and xylene with up to a few percent of methylene chloride.
• the isopropanol may be replaced wholly or partially with lower boiling point aliphatic alcohols such as ethanol.
• U.S. Pat. No. 3,743,542 describes a method for removing paint from metal surfaces by boiling a solvent or solvent mixture and contacting the painted metal surface with the vapors of the solvent mixture, preferably while refluxing the vapors in a closed system. It is especially useful for removing durable paints such as those based on vinyl, acrylic, or epoxy resins.
• the stripping composition comprises hydrogenated aromatic solvents and aliphatic alcohols.
• U.S. Pat. No. Re 27,432 is directed to a process for removing polymeric materials from processing equipment. It teaches numerous solvents known for dissolving vinyl halides such as trimethylene oxide, tetramethyl urea, dimethyl acetamide, tetrahydrofuran, cyclohexanone, cyclopentanone, cyclohexene oxide, diethyl acetamide, methyl ethyl ketone, and dioxane. It also teaches that these solvents vary in dissolution strength with the molecular weight of the compound to be dissolved and that tetrahydrofuran successfully removes both homopolymer and co-polymer contaminants having low or high molecular weights.
• solvents such as trimethylene oxide, tetramethyl urea, dimethyl acetamide, tetrahydrofuran, cyclohexanone, cyclopentanone, cyclohexene oxide, diethyl acetamide,
• U.S. Pat. No. 3,784,477 relates to removal of paints, varnishes, and similar finishes from wood and metal objects without damage to grain or glue joints. It teaches that xylene or aromatic naphthas can be used as an extender for dimethylformamide or dimethyl acetamide, with little change in paint removal activity, and further that xylene can be diluted or extended freely with methyl alcohol up to about 20% of its weight.
• Trioxane-containing lacquer removers for alkyd resins are disclosed in German Offenlegungsschrift No. 2,118,870. They consist of 4-7:1-3 parts diol acetols, such as 1,3-dioxolane, and trioxane for retention of the volatile acetals. They optionally contain ethyl cellulose.
• Substantially all currently used strippers contain chlorinated hydrocarbons and particularly methylene chloride which is a potentially harmful solvent. There is accordingly a need for a solvent having fast lifting speed for common coatings which is also harmless to the user.
• a typical Methylene Chloride Remover contains 70-85% methylene chloride, 5-10% alcohol, and 0-10% hydrocarbon solvent or ketones, the remainder being paraffin wax, methylcellulose, an amine, and surfactants or emulsifiers.
• trioxane is a very fast and effective solvent for lifting common coatings and that its solubility parameters can be modified by admixing an aromatic hydrocarbon and an aliphatic alcohol.
• aromatic hydrocarbons include benzene, toluene, xylenes, and ethylbenzene, a xylene or a mixture of xylenes being the preferred aromatic solvent.
• alkylbenzenes such as di-ethylbenzene, isopropyl benzene, otho-ethyltoluene, trimethylbenzenes, and cumene are reasonably satisfactory, if the alkane end is not more than a C 5 hydrocarbon, to form a liquid composition which is an effective coatings stripper.
• the aliphatic alcohol may be selected from the group consisting of methanol, ethanol, isopropanol, n-propanol, and butanol, the solubility of trioxane being progressively less in this series.
• Methanol is the preferred solvent.
• the composition is suitably further modified by adding waxes or oils to reduce evaporation and by adding thickeners to reduce flow so that it can be used for vertical surface stripping.
• the preferred composition for use at ambient temperatures is approximately 33% methanol, 33% xylene, and 33% trioxane.
• the content of trioxane can be lowered, but doing so increases the time required for removal of coatings.
• the solubility of trioxane is about 35% by weight. However, to provide a margin of safety in the event that the temperature drops, 33% is preferred.
• This coatings stripper is less dense than the methylene chloride strippers and is 66% water soluble.
• Trioxane is more like methylene chloride in structure than is dioxane, dimethylformamide, tetrahydrofuran, or tetramethylene oxide. Methylene chloride, however, is very low on hydrogen bonding as compared to trioxane. In the solvent composition of this invention, more aromatics are consequently needed to counterbalance the hydrogen bonding of trioxane. The wetting ability of the alcohol is needed to add a proton donor for hydrogen bonding.
• This paint stripper composition is useful for removing or stripping a wide variety of coatings such as paints, varnishes, enamels, lacquers, and the like, and more particularly neoprenes, polyesters, polycarbonates, silicon elastomers, phenolics, vinyl halide polymers and copolymers, acrylates, and polyvinyl alcohol coatings at ambient temperatures. It is particularly suitable for alkyd, latex, and urethane paints and for varnishes.
• Trioxane as used herein is a cyclic trimer of formaldehyde having the structural formula below: ##STR1##
• trioxane When trioxane is dissolved in methanol and other solvents, heat is absorbed so that the solubility of trioxane in methanol and similar solvents increases with increasing temperature.
• the solubility of trioxane in methanol is shown in the following table:
• Stripper compositions based on trioxane can be useful for warm-to-hot baths (35°-60° C.) that offer many of the advantages of conventional immersion-type removers without the disadvantages of volatility and/or causticity. Moreover, mixtures of alcohols can be utilized in such baths to provide low volatility and adequate solvency.
• trioxane Using a modification of the Crowley methhod to determine the hydrogen bonding capability of trioxane, solutions of trioxane were prepared with 8% and 20% trioxane. This solvent system was used to prepare 0.1M EtOd solutions for FT-IR.
• trioxane is similar to esters and methylene chloride.
• a stripper composition was prepared to determine the similarity of trioxane to CH 2 Cl 2 and its usefulness as a stipper.
• the composition contained 100 grams trioxane, 100 grams toluene, and 100 grams n-butanol. These materials were mixed and filtered. Endothermic behavior was noted. The solution was then applied to a sample of white paint of unknown composition which was more than 2 years old. The white paint lifted.
• Example 2 The composition of Example 2 was tested on a varnish and also resulted in lifting the coating.
• Example 2 The composition of Example 2 was additionally applied to an epoxy paint and similarly resulted in lifting.
• Neat methylene chloride was applied to the paint, varnish, and epoxy coatings of Examples 2, 3, and 4 and also caused lifting but did so more quickly.
• Example No. 11 Six paint stripper solutions, weighing 500 grams, were made up by weight. The trioxane caused a strong endotherm.
• the formulation in Example No. 11 was prepared according to German Offenlegungsschrift No. 2,123,563, using ethyl acetate. These formulations are as follows:
• Example 8 a 50% solution of trioxane in methanol was attempted, but the trioxane was only partially soluble, so that it was considered to be a saturated solution. In Example 9, the trioxane was also not totally soluble and was similarly used as a saturated solution.
• test samples were prepared on glass panels, as a first set of 48 panels, by using a six mil drawdown blade with commercial paints. The panels were 6 inches by 8 inches. The coatings were allowed to dry for 48 hours and then tested at ambient temperatures. A second set was also dried for 48 hours and then cured in an oven at 120° F. for 7 days before testing at ambient temperature (24°-25° C.). These coatings were an alkyd, a latex, a urethane, and a varnish; they were purchased at a retail outlet.
• the alkyd coating was made with Rust Preventative Ace Quick Drying Exterior Enamel Alkyd #197-23 Dutch Orange.
• the latex coating was made with Ace-Tone Acrylic Latex Semi-Gloss Enamel #186-114 Sea Green Interior.
• the varnish was prepared with McCloskey Heirloom Clear Varnish High Gloss #0092.
• the urethane coating was made with Deftane Clear Gloss #1, Polyurethane Finish Interior/Exterior.
• a test of an epoxy paint was made by coating two steel panels with a very hard-to-strip epoxy of a proprietary formulation. After curing, the panels were exposed to the solvent compositions of Examples 6 and 12. Neither composition touched the coating in 5 minutes (300 seconds). After 30 minutes, the composition of Example 12 released the coating in part, and the composition of Example 6 loosened the film slightly. Neither did the job well.
• a stripper composition is made of 33% xylene, 33% n-butanol, and 33% trioxane, as in Example 9, and is heated to 35° C. All of the trioxane appears to be in solution. A piece of wood, coated with an obviously old alkyd paint, is dipped into the warm stripper. Lifting activity is noted promptly.
• Another stripper composition is prepared with 25% of xylene, 25% of a 95% ethanol/5% water solution, and 50% of trioxane. At 25° C., trioxane should dissolve in a 95.5% ethanol/water solvent to the extent of 28 parts to 100. Assuming that the same solubility holds in this composition, it is 32% xylene, 32% ethanol/H 2 O, and 36% trioxane. A piece of the same wood coated with the same alkyd paint of unknown age is dipped into the stripper at ambient temperature and lift off is observed within a short time.
• Example 15 The composition of Example 15 is heated to 35° C., and a piece of the same painted wood is dipped therein. Lifting of the coating is observed quickly.
• composition of Examples 15 and 16 is heated to 45° C., and a piece of the same wood coated with the same alkyd paint is dipped thereinto. Lift off is observed very quickly.
• the stripper composition of Examples 15-17 is heated to 60° C., and a piece of the same painted wood is dipped thereinto, with lift off being observed immediately.
• trioxane can be formulated as a slurry which then can be used at an elevated temperature at which it is in solution. These compositions should therefore be suitable for hot dip usage in a stripper tank.

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• Chemical & Material Sciences (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Paints Or Removers (AREA)
• Cleaning Or Drying Semiconductors (AREA)
• Detergent Compositions (AREA)

Priority Applications (9)

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Publications (1)

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Cited By (12)

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Citations (9)

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• 1988
  • 1988-06-10 US US07/205,143 patent/US4830772A/en not_active Expired - Fee Related
• 1989
  • 1989-06-08 CA CA000602112A patent/CA1335250C/en not_active Expired - Fee Related
  • 1989-06-09 JP JP1148231A patent/JPH0713211B2/ja not_active Expired - Lifetime
  • 1989-06-09 EP EP89305825A patent/EP0346130B1/de not_active Expired - Lifetime
  • 1989-06-09 AT AT89305825T patent/ATE115167T1/de not_active IP Right Cessation
  • 1989-06-09 DE DE68919754T patent/DE68919754T2/de not_active Expired - Fee Related
  • 1989-06-10 KR KR1019890008070A patent/KR940000533B1/ko not_active IP Right Cessation
  • 1989-06-10 CN CN89106266A patent/CN1026989C/zh not_active Expired - Fee Related
  • 1989-06-12 BR BR898902765A patent/BR8902765A/pt not_active Application Discontinuation

Patent Citations (9)

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